Aromatic-free mineral oil rust inhibiting compositions



Patented May 5, 1953 UITED ST AROMATIC-FREE MINERAL OIL RUST INHIBITING COMPOSETIONS No Drawing. Application March 8, 1951, Serial No. 214,648

Claims.

This invention relates to rust preventing oil compositions and more particularly to oil compositions which tend to inhibit rusting and corrosion of metal and rubber parts.

In connection with the manufacture of antifreezes from freezing point depressants such as methanol, glycerine, ethylene glycol, denatured ethyl alcohol, etc., experience has indicated that it is necessary to employ a rust inhibitor in the composition. The purpose of the rust inhibitor is to prevent the corrosion of the various metals used in the construction of automotive engines. e. g., aluminum, lead, tin, iron, copper, as well as prevent deterioration of rubber hose used in radiator connections. This corrosion is attributable to the combined action of water and oxygen.

It has now been found that certain specific mineral oil solutions are ideally adapted to provide non-corrosive liquids when added to the before-mentioned anti-freezes.

The ingredients of the mineral oil rust inhibiting solutions are thus as follows: a petroleum mineral oil, ethyleneglycol monobutylether, an oil-soluble sodium petroleum sulfonate and an agent selected from the group consisting of pentaerythritol monooleate or a mixture of sorbitan monolaurate and sorbitan monooleate. The absence of any of these listed ingredients results in unsatisfactory compositions. The components cooperate in obtaining the desired solubility, anti-corrosion and rubber-swelling properties. The quantities of each component have also been found to be critical and are detailed below.

The mineral oils employed are the oils prepared by the well-known exhaustive sulfuric acid treatment of petroleum oil. They are known in the art as Bayol D, Bayol F, etc., which are white petroleum oils and light gas oil fractions that are naphthenic and paraffinic but substantially free or aromatics. They have a viscosity of about 35-60 SUS at 100 F. Mixtures of these mineral oils may also be employed. A typical inspection of Bayol D is as follows:

Specific gravity 0775-0825 A. S. T. M. Dist, F.:

I. B. P. 400

F. B. P. 505 Mixed aniline point, F 175 Flash point, F. 160 Unsulfonated residue 97% Sulfur, lamp 0.02 Color, Saybolt 25 Percent Aromatics Trace The mineral oil is employed in an amount of from 80.5 to 62 weight percent.

sorbitan mcnolaurate and sorbitan monooleate must both be employed or, in place thereof, pentaerythritol monooleate alone can be used. These are the only agents that have been found useful in the compositions of this invention for obtaining the desired characteristics. The employment of sorbitan monolaurate without sorbitan monooleate, or vice versa, or the absence of both as well as pentaerythritol monooleate gives undesirable results. Sorbitan monolaurate is employed in an amount of from 3 to 6 weight percent and sorbitan monooleate is employed in an amount of from 0.75 to 1.5 weight percent.

Ethyleneglycol monobutylether is employed in an amount of from 0.75 to 1.5 weight percent. Its absence leads to undesirable corrosion and rubber-swelling characteristics.

An oil-soluble sodium petroleum sulfonate is employed in an amount of from 15 to 30 weight percent. These contribute to the desired solubility and corrosion-inhibiting characteristics. The petroleum sulfonates are prepared by the well-known sulfuric acid treatment of petroleum fractions and the oil-soluble sodium petroleum sulfonates are alkyl aryl sulfonates having a minimum average molecular weight of about 400. The range falls usually between 400-500.

When pentaerythritol monooleate is substituted. for sorbitan monolaurate and sorbitan monooleate, the ranges of the ingredients employed are as follows:

Weight percent Sodium sulfonates 15 to 30 Ethyleneglycol monobutylether 0.75 to 1.5 Pentaerythritol monooleate 2 to 4 Mineral oil 82.25 to 64.5

EXAMPLE I Rust preventive compositions for anti-freezes Various compositions were prepared utilizing all the essential components of this invention in the indicated quantities. Formulations were also hibitor. A trace of undissolved material is allowed.

(b) Corrosion and rubber sweZZing.-The corrosion test was carried out by placing small test pieces of aluminum, copper, iron, tin and a small piece of rubber gasket material commonly used in automobiles in a flask containing equal parts of anti-freeze and water. The flask was equipped with a reflux condenser and maintained at 185 F. for 100 hours. The metal strips were then examined for staining and for plating of one metal to another. The rubber was examined for swelling and softening. The test pieces were not weighed in this test; visual observations were used to evaluate the degree of deterioration. Only slight staining of the metal pieces and no plating of one metal to another is permitted. No deterioration of the rubber is allowed. The results follow.

Thecompositions must rate "(3 on each of the three criteria for commercial acceptability.

Rust preventive compositions for antifreeze neutralize any acids formed by oxidation of the solute.

The aqueous liquids stabilized by the oil compositions according to the present invention are not limited to use in automobile radiators, as they may likewise be used with equal effectiveness in all radiators for gasoline engines, in circulating hot water systems, steam boilers, and in other places where it is desired to prevent gorrosion of metal surfaces in contact with aqueous liquids. The quantity of the rust inhibiting oil added to the anti-freeze may be varied as desired.

The corrosion inhibitor of the present invention effectively prevents corrosion of metals without interfering with the heat transfer between metal and the aqueous liquid containing the corrosion inhibitors. Furthermore, the oil is uniformly dispersed throughout the anti-freeze solution and has no tendency to agglomerate in any one particular place, or to clog radiator tubes and the like, as ordinary water-immiscible oils will do in the absence of emulsifying agents.

It is to be understood that this invention is not limited to the specific examples which have been offered merely as illustrations and that modifications may be made without departing from the spirit of this invention.

What is claimed is:

1. A corrosion inhibiting composition comprising a substantially aromatic-free mineraloil containing dissolved therein an oil-soluble sodium Experiments Designation Corrosion Rubber Swelling monooleate 1 Composition of anti-freeze:

0.5% water rust preventative base oil 98.0% alcohol denatured. Evaluation:

Good (G) Fair (F) a Poor (P) water-alcohol.

, Several results are apparent. Experiments designated 1 and 2 indicate that sodium sulfonates plus sorbitan monooleate, or sodium sulfonates plus sorbitan monolaurate and sorbitan monooleate are unsatisfactory in the absence of ethyleneglycol monobutylether. The presence of 1% ethyleneglycol monobutylether, as in experiment 3, gives a very satisfactory rust preventative; Experiment 4 indicates that the reduction by one-half of the sorbitan monolaurate, sorbitan monooleate and ethyleneglycol monobutylether of experiment 3 results in poorer compositions. Experiment 8 shows the necessity for the presence of sodium sulfonates.

Other ingredients may be added, to the antifreeze solutions for various purposes. such as tri' ethanolamine or ortho toluidine. which serve to Corrosion test metals Al, Cu, .Fe, Sn plus rubber reflux for hours in 50/511 petroleum sulfonate in an amount of 15 to 30 Weight per cent, ethyleneglycol monobutylether in an amount of 0.75 to 1.5 weight per cent, sorbitan monolaurate in an amount of from 3 to 6 weight per cent and sorbitan monooleate in an amount of 0.75 to 1.5 weight per cent.

2. A corrosion inhibiting composition comprising a substantially aromatic-free mineral oil containing dissolved therein an oil-soluble sodium petroleum sulfonate in an amount of 15 to 30 weight per cent, ethyleneglycol monobutylether inan amount of 0.75 to 1.5- weight per cent and entaerythritol monooleate inan amount of 2- to 4 weight per cent.

3. A corrosion inhibiting composition consisting essentially of a substantially aromatic-free mineral oil solution having approximately the following weight per cent composition:

Per cent by weight Oil-soluble sodium petroleum sulphonate- 20 Sorbitan monolaurate 4 Sorbitan monooleate 1 Ethyleneglycol monobutylether 1 Mineral oil '74 4. A corrosion inhibiting composition consisting essentially of a substantially aromatic-free mineral oil solution having approximately the following weight per cent composition:

Per cent by weight Oil-soluble sodium petroleum sulphonate 20 Ethyleneglycol monobutylether 1 Pentaerythritol monooleate 3 Mineral oil '76 5. A corrosion inhibiting composition comprising a substantially aromatic-free mineral oil containing dissolved therein an oil-soluble sodium petroleum sulfonate in an amount of 15 to 0 weight per cent, ethyleneglycol monobutylether in an amount of 0.75 to 1.5 weight per cent, and an agent selected from the group consisting of (l) a mixture of sorbitan monolaurate in an amount of from 3 to 6 weight per cent and sorbitan monooleate in an amount of 0.75 to 1.5 weight per cent, and (2) pentaerythritol monooleate in an amount of 2 to 4 weight per cent.

THOMAS W. DIXON. LORNE W. SPROULE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,334,158 Von Fuchs et al Nov. 9, 1943 2,371,142 Barnum et a1 Mar. 13, 1945 2,434,490 Duncan Jan. 13, 1948 2,482,517 Schiermeier et a1. Sept. 20, 1949 

5. A CORROSION INHIBITING COMPOSITION COMPRISING A SUBSTANTIALLY AROMATIC-FREE MINERAL OIL CONTAINING DISSOLVED THEREIN AN OIL-SOLUBLE SODIUM PETROLEUM SULFONATE IN AN AMOUNT OF 15 TO 30 WEIGHT PER CENT, ETHYLENEGLYCOL MONOBUTYLETHER IN AN AMOUNT OF 0.75 TO 1.5 WEIGHT PER CENT, AND AN AGENT SELECTED FROM THE GROUP CONSISTING OF (1) A MIXTURE OF SORBITAN MONOLAURATE IN AN AMOUNT OF FROM 3 TO 6 WEIGHT PER CENT AND SORBITAN MONOOLEATE IN AN AMOUNT OF 0.75 TO 1.5 WEIGHT PER CENT, AND (2) PENTAERYTHRITOL MONOOLEATE IN AN AMOUNT OF 2 TO 4 WEIGHT PER CENT. 